Unicycive Therapeutics Receives FDA Complete Response Letter for OLC

Unicycive Therapeutics, Inc., a clinical-stage biotechnology company based in Los Altos, California, announced on June 30, 2025, that it has received a Complete Response Letter (CRL) from the U.S. Food and Drug Administration (FDA) regarding its New Drug Application (NDA) for oxylanthanum carbonate (OLC), a treatment for hyperphosphatemia in patients with chronic kidney disease (CKD) on dialysis. The CRL cited deficiencies identified at a third-party manufacturing vendor unrelated to OLC itself, raising concerns about the manufacturing quality control processes but not about the clinical safety or efficacy of the drug.

According to Dr. Shalabh Gupta, Chief Executive Officer of Unicycive, the company plans to request a Type A meeting with the FDA to discuss a strategy for addressing the concerns raised in the CRL. “We remain optimistic about our ability to bring this promising new treatment option to patients with CKD who are managing hyperphosphatemia,” Dr. Gupta stated in the company’s press release. Unicycive has identified a second manufacturing vendor that has already produced OLC drug product, which could help resolve the clinical manufacturing and controls (CMC) issues raised in the CRL.

The FDA’s CRL comes after a routine review of the NDA submission, which included data from three clinical studies: a Phase 1 study in healthy volunteers, a bioequivalence study, and a tolerability study in CKD patients on dialysis. Notably, the FDA did not highlight any additional concerns regarding the CMC documentation or the testing of OLC itself. This reinforces the potential of OLC as a treatment option for hyperphosphatemia, a serious condition affecting nearly all patients with End Stage Renal Disease (ESRD).

Hyperphosphatemia is often exacerbated by dietary phosphorus intake, necessitating the use of oral phosphate binders to manage phosphate levels effectively. As highlighted in a study by Dr. Jessica Flythe, a nephrologist at the University of North Carolina, and published in Kidney360 in May 2023, uncontrolled hyperphosphatemia is associated with increased mortality and hospitalization rates among CKD patients on dialysis (Flythe, J.E. 2023). Annually, over 450,000 individuals in the U.S. require medication to control their phosphate levels, underscoring the critical need for effective treatments.

Unicycive’s OLC utilizes proprietary nanoparticle technology to provide high phosphate binding potency, potentially reducing the pill burden for patients. The investigational drug is protected by a strong global patent portfolio, with exclusivity until 2031, and potential extensions until 2035.

As Unicycive moves forward, the implications of the FDA’s CRL may extend beyond the company. The resolution of the manufacturing issues is essential not only for the company’s future but also for the broader landscape of treatments available for CKD patients. Industry analysts suggest that successful navigation of regulatory hurdles could enhance investor confidence and position Unicycive favorably among its peers in the biotechnology sector.

In conclusion, while the CRL represents a setback for Unicycive Therapeutics, the company’s proactive approach in identifying alternative manufacturing solutions and seeking alignment with the FDA may allow it to overcome these challenges. The importance of OLC as a potential treatment for hyperphosphatemia cannot be overstated, particularly given the rising prevalence of CKD and associated complications. The coming months will be crucial as Unicycive updates stakeholders on its progress and next steps in the regulatory process, with hopes of bringing OLC to market to address a significant unmet medical need.